This invention lies in the field of thermostatic control of temperature in hotel or motel rooms etc. It can use any of the presently known and used temperature sensitive switches to control the heating and/or cooling elements when the room temperature is at a second selected temperature. The currently used thermostatic switches are set manually and must be changed manually if there is to be a different setting of operating temperature. This invention lies in a feature which utilizes the entrance or departure of persons from the room to control the temperature of the room. This is done automatically, by the operation of a second set of thermostatic switches. It's action is dependent on the presence or absence of a magnet attached to and made part of a door chain. So long as the occupant of that room is present, the more comfortable temperatures are used. This is arranged by the application of the door chain to its normal locking receptacle which includes, in this invention, a switch responsive to the presence of a magnet in the chain.